Support and organic electroluminescence element comprising the support

ABSTRACT

Disclosed is a support which comprises a flexible substrate and provided thereon, one or two or more polymer layers and one or two or more sealing layers, wherein at least one of the polymer layers and the sealing layers is formed by a process comprising the steps of exciting a reactive gas at a space between opposed electrodes at atmospheric pressure or approximately atmospheric pressure by electric discharge to be in the plasma state, and exposing the flexible substrate, the polymer layer or the sealing layer to the reactive gas in the plasma state.

FIELD OF THE INVENTION

[0001] This invention relates to a support with excellent moisturesealing ability and without layer exfoliation, which is useful for adisplay or an electronic device, and an organic electroluminescenceelement employing the support.

BACKGROUND OF THE INVENTION

[0002] A glass plate has been used in view of thermal stability ortransparency, as a base plate of a display such as a liquid crystaldisplay or an organic electroluminescence display or as a base plate ofan electronic device such as CCD or a CMOS sensor.

[0003] In recent years, as portable information terminal units such as acellular phone spread, use of a plastic substrate, which is flexible,light and difficult to be damaged, has been studied in place for a glasssubstrate, which is heavy or easy to be damaged, in a display or anelectro-optical device provided in the terminal units.

[0004] However, since the plastic substrate has a moisturepenetrability, it is difficult to be applied to a device such as anorganic electroluminescence display (hereinafter referred to also as anorganic electroluminescence element) which is damaged by moisture tocause deterioration of its performance. Accordingly, how to sealmoisture is a problem.

[0005] In order to overcome the above problem, in WO-0036665 is proposeda layer (hereinafter referred to as proposed prior art) with a highmoisture sealing ability, a composite layer employing silica with a lowmoisture penetrability and an acryl monomer, which is formed bydepositing on a substrate a monomer containing an acryl monomer,polymerizing the deposited monomer, depositing silica, and furtherdepositing a monomer containing an acryl monomer and polymerizing thedeposited monomer. However, in this literature, concrete materials usedor concrete experiment conditions are not disclosed. The presentinventors have traced the proposed prior art, and as a result, they havefound that the proposed prior art has problem in that the formed polymerlayer and inorganic substance layer are likely to exfoliate duringhandling and moisture penetrates in the portions where the layersexfoliate.

SUMMARY OF THE INVENTION

[0006] Accordingly, an object of the invention is to provide a supportwith excellent moisture sealing ability and without layer exfoliation,which is useful for a display or an electronic device, and to provide anorganic electroluminescence element with long life employing thesupport.

BRIEF EXPLANATION OF THE DRAWING

[0007]FIG. 1 shows one embodiment of a plasma discharge treatmentchamber.

[0008]FIG. 2(a) and FIG. 2(b) show examples of roll electrode.

[0009]FIG. 3(a) and FIG. 3(b) show perspective views of fixed electrode.

[0010]FIG. 4 shows a plasma discharge chamber in which the fixedprismatic electrodes are arranged around the circumference of the rollelectrode.

[0011]FIG. 5 shows a schematic view of one embodiment of the plasmalayer formation apparatus.

[0012]FIG. 6 shows a schematic view of another plasma layer formationapparatus.

[0013]FIG. 7 shows a sectional view of one embodiment of the support ofthe invention.

[0014]FIG. 8 shows a sectional view of another embodiment of the supportof the invention.

[0015]FIG. 9 shows a sectional view of one embodiment of the organicelectroluminescence element of the invention.

[0016]FIG. 10 shows a schematic view of another embodiment of theorganic EL element of the invention.

[0017]FIG. 11 shows a schematic view of still another embodiment of theorganic electroluminescence element of the invention.

DETAILED DESCRIPTION OF THE INVENTION

[0018] The object of the invention has been attained by the followingconstitutions:

[0019] 1-1. A support comprising a flexible substrate and providedthereon, one or two or more polymer layers and one or two or moresealing layers, wherein at least one of the polymer layers and thesealing layers is formed by a process comprising the steps of exciting areactive gas at a space between opposed electrodes at atmosphericpressure or approximately atmospheric pressure by electric discharge tobe in the plasma state, and exposing the flexible substrate, the polymerlayer or the sealing layer to the reactive gas in the plasma state.

[0020] 1-2. The support of item 1-1 above, wherein the polymer layercontains a polymeric compound, and the sealing layer contains a metaloxide, a metal nitride or a metal oxide nitride.

[0021] 1-3. The support of item 1-2 above, wherein the polymericcompound is obtained by polymerization of a monomer comprising a vinylcompound or an acetylene compound, the metal oxide is a compoundselected from silicon oxide, titanium oxide, indium oxide, tin oxide,indium tin oxide (ITO), or alumina, the metal nitride is a compoundselected from silicon nitride or titanium nitride, the metal oxidenitride is a compound selected from silicon oxide nitride, or titaniumoxide nitride, and the reactive gas is an organometallic compound or themonomer.

[0022] 1-4. The support of item 1-3 above, wherein the organometalliccompound is an organosilicon compound, an organotitanium compound, anorganotin compound, an organoindium compound, an organoaluminumcompound, or a composite compound thereof.

[0023] 1-5. The support of item 1-4 above, wherein the organosiliconcompound is a compound represented by formula (1), (2), (3), or (4),

[0024] Formula (1)

[0025] wherein R₂₁, R₂₂, R₂₃, R₂₄, R₂₅, and R₂₆ independently representa hydrogen atom or a monovalent substituent, and n1 represents a naturalnumber.

[0026] Formula (2)

[0027] wherein R₃₁ and R₃₂ independently represent a hydrogen atom or amonovalent substituent, and n2 represents a natural number.

(R₄₁)_(n)Si(R₄₂)(_(4−n))   Formula (3)

[0028] wherein R₄₁ and R₄₂ independently represent a hydrogen atom or amonovalent substituent, and n represents an integer of from 0 to 3.

[0029] wherein A represents a single bond or a divalent group, R₅₁, R₅₂,R₅₃, R₅₄, and R₅₅ independently represent a hydrogen atom, a halogenatom, an alkyl group, a cycloalkyl group, an alkenyl group, an arylgroup, an aromatic heterocyclic group, an amino group or a cyano group,provided that R₅₁ and R₅₂, or R₅₄ and R₅₅ may combine with each other toform a ring.

[0030] 1-6. The support of item 1-5 above, wherein the compoundrepresented by formula (4) is a compound represented by formula (5),

[0031] wherein R₆₁, R₆₂, R₆₃, R₆₄, R₆₅, and R₆₆ independently representa hydrogen atom, a halogen atom, an alkyl group, a cycloalkyl group, analkenyl group, an aryl group, or an aromatic heterocyclic group.

[0032] 1-7. The support of item 1-3 above, wherein the content of themetal oxide, the metal nitride and/or the metal oxide nitride in thesealing layer is not less than 90% by weight.

[0033] 1-8. The support of claim 1-1 above, wherein the sealing layercontains carbon in an amount of from 0.2 to 5% by weight.

[0034] 1-9. The support of item 1-1 above, wherein the sealing layer hasa thickness of from 50 to 2000 nm, and the polymer layer has a thicknessof from 50 to 2000 nm.

[0035] 1-10. The support of item 1-1 above, wherein at least one of thesealing layers is formed by a process comprising the steps of exciting areactive gas at a space between opposed electrodes at atmosphericpressure or approximately atmospheric pressure by discharge to be in theplasma state, and exposing the flexible substrate to the reactive gas inthe plasma state.

[0036] 1-11. The support of item 1-1 above, wherein the sealing layer isformed by a process comprising the steps of exciting a reactive gas at aspace between opposed electrodes at atmospheric pressure orapproximately atmospheric pressure by discharge to be in the plasmastate, the discharge being induced by supply of a power of not less than1 W/cm² with a frequency exceeding 100 kHz, and exposing the flexiblesubstrate to the reactive gas in the plasma state.

[0037] 1-12. An organic electroluminescence element comprising asupport, wherein the support comprises a flexible substrate and providedthereon, one or two or more polymer layers and one or two or moresealing layers, wherein at least one of the polymer layers and thesealing layers is formed by a process comprising the steps of exciting areactive gas at a space between opposed electrodes at atmosphericpressure or approximately atmospheric pressure by discharge to be in theplasma state, and exposing the flexible substrate to the reactive gas inthe plasma state.

[0038] 1-13. A support comprising a substrate and provided thereon, atleast two layers containing a metal oxide, a metal nitride or a metalnitride oxide, the two layers being different in carbon concentration,wherein at least one of the layers is formed by a process comprising thesteps of exciting a reactive gas at a space between opposed electrodesat atmospheric pressure or approximately atmospheric pressure byelectric discharge to be in the plasma state, and exposing the substrateor the layer to the reactive gas in the plasma state.

[0039] 2-1. A support comprising a flexible substrate and providedthereon, a polymer layer and a sealing layer, wherein at least one ofthe polymer layer and the sealing layer, is a layer formed by exciting areactive gas at a space between opposed electrodes at atmosphericpressure or approximately atmospheric pressure by discharge to be in theplasma state, and exposing the flexible substrate to the reactive gas inthe plasma state.

[0040] 2-2. The support of item 2-1 above, wherein the polymer layercontains a polymeric compound, and the sealing layer contains a metaloxide, a metal nitride, or a metal oxide nitride.

[0041] 2-3. The support of item 2-1 or 2-2 above, wherein the sealinglayer is formed by discharge induced by supply of a power of not lessthan 1 W/cm² with a frequency exceeding 100 kHz.

[0042] 2-4. An organic electroluminescence element comprising thesupport of any one of items 2-1 through 2-3.

[0043] The present inventors have made an extensive study, and as aresult, they have developed a support having the constitution describedabove, which overcomes the above problem, and also developed an organicelectroluminescence element (hereinafter referred to also as organic ELelement) with a long life employing the support.

[0044] As described above, in recent years, use of a plastic substrate,which is flexible, light and difficult to be damaged, has been studiedto replace a glass substrate, which is heavy or easy to be damaged, incrystal liquid or EL displays or electro-optical devices.

[0045] However, plastic substrates currently manufactured haverelatively high moisture penetrability and contain some moisture.Therefore, the plastic substrates, when used in an organicelectroluminescence display, have problem in that the moisture graduallydiffuses in the display, and the diffused moisture lowers durability ofthe display.

[0046] In order to overcome the above problem, attempts have been madeto obtain a support applicable to various electronic devices in which aplastic sheet is subjected to a certain treatment to minimize moisturepenetrability or to reduce the moisture content. For example, in view ofthe above proposed prior art, an attempt has been made in which a thinlayer of silica or glass with low moisture penetrability is formed on aplastic substrate to obtain a composite material. However, the thinlayer has defects, and a specific layer thickness not less than acertain value is necessary to lower moisture penetrability and seal anymoisture in the support.

[0047] When a layer containing silica or containing an inorganicmaterial with low moisture penetrability such as a metal oxide, a metalnitride or a metal oxide nitride (in an amount of at least 90% byweight) is formed on a plastic substrate with a thickness sufficient tominimize moisture penetrability to obtain a support, the resultingsupport loses flexibility of the plastic substrate capable of beingfolded and causes layer exfoliation, which lowers moisture sealingability.

[0048] Provision on a substrate of plural layers, not a single layer,helps to restrain layer exfoliation to some degree, which needs an extraprocess and increases manufacturing cost. Further, since it is essentialto control physical properties of each layer, the plural layers are notnecessarily preferable.

[0049] The invention is a support comprising a flexible substrate andprovided thereon, a polymer layer and a sealing layer, wherein at leastone of the polymer layer and the sealing layer, is a layer formed byexciting a reactive gas at a space between opposed electrodes atatmospheric pressure or approximately atmospheric pressure by dischargeto be in the plasma state, and exposing the flexible substrate to thereactive gas in the plasma state. The present inventors have found thatthe support described above is a support with low moisturepenetrability, reduced deterioration due to fold, and excellent moisturesealing ability and without layer exfoliation, and they have completedthis invention.

[0050] The support of the invention is a support comprising a flexiblesubstrate and provided thereon, a polymer layer and a sealing layer,wherein at least one of the polymer layer and the sealing layer is alayer formed according to plasma treating of the flexible substrate atatmospheric pressure or approximately atmospheric pressure, andpreferably a support comprising a flexible substrate and providedthereon, a polymer layer and a sealing layer, wherein at least one ofthe sealing layers is a layer formed according to plasma treatment ofthe flexible substrate at atmospheric pressure or approximatelyatmospheric pressure. It is also preferred that the polymer layer is alayer formed according to plasma treatment of the flexible substrate atatmospheric pressure or approximately atmospheric pressure.

[0051] The sealing layer used in the invention will be explained below.

[0052] A metal oxide, a metal nitride and a metal oxide nitride aresuitable for a material with low moisture penetrability. These form arelatively hard layer with high density.

[0053] A sealing layer comprising a metal oxide, a metal nitride or ametal oxide nitride can be obtained according to a method carrying outplasma treatment at atmospheric pressure or approximately atmosphericpressure, that is, an atmospheric pressure plasma method which comprisesexciting a reactive gas, an organometallic compound between opposedelectrodes to be in a plasma state, and exposing a substrate to thereactive gas in the plasma state to form the sealing layer on thesubstrate. Herein, atmospheric pressure or approximately atmosphericpressure herein referred to implies approximately atmospheric pressure,and typically a pressure of 20 kPa to 110 kPa, and preferably 93 kPa to104 kPa.

[0054] The reactive gas used in the atmospheric pressure plasma methodis preferably an organometallic compound. Flexibility of the sealinglayer can be controlled by employing the organometallic compound as areactive gas and by adjusting the plasma generation conditions. Thecarbon content of the sealing layer can be controlled adjusting theplasma generation conditions. Flexibility of the sealing layer variesdepending on the carbon content of the layer.

[0055] Since particles such as ions from the reactive gas used arepresent between the opposed electrodes at a high concentration in theatmospheric plasma method, carbon derived from the organometalliccompound used is likely to remain in the formed layer. A slight amountof carbon is preferably contained in the layer to provide flexibility tothe layer and increase abrasion resistance of the layer. The carboncontent of the layer is preferably from 0.2 to 5% by weight. When thecarbon content exceeds 5% by weight, layer properties such as refractiveindex may change with time, which is not desirable.

[0056] In order to obtain a layer with a carbon content of from 0.2 to5% by weight, discharge is preferably induced supplying a power of notless than 1 W/cm² with a frequency exceeding 100 kHz. Further, thewaveform of a high frequency voltage applied is preferably a continuoussine wave.

[0057] The carbon content of the layer depends mainly on the frequencyand power supplied from a power source, and decreases as frequency ofvoltage applied to electrodes is raised or power supplied is increased.When a hydrogen gas is incorporated in the mixed gas used, carbon atomsare likely to be consumed, and the carbon content can be controlledthereby also.

[0058] A sealing layer will be explained below, which is formedaccording to a plasma method carried out at atmospheric pressure orapproximately atmospheric pressure, employing an organometallic compoundas the reactive gas.

[0059] The substrate used in the invention may be any as long as it isflexible. The flexible substrate may be comprised of a single sheet,plural sheets or a sheet whose surface is subjected to subbingtreatment. The flexible substrate preferably used is a resin substrate.Examples of the substrate include a polyester film such as apolyethylene terephthalate or polyethylene naphthalate film, apolyethylene film, a polypropylene film, a cellophane film, a film of acellulose ester such as cellulose diacetate, cellulose triacetate,cellulose acetate butyrate, cellulose acetate propionate, celluloseacetate phthalate, cellulose nitrate or their derivative, apolyvinylidene chloride film, a polyvinyl alcohol film, anethylene-vinyl alcohol film, a syndiotactic polystyrene film, apolycarbonate film, a norbornene resin film, a polymethylpentene film, apolyetherketone film, a polyimide film, a polyethersulfone film, apolysulfone film, a polyetherketoneimide film, a polyamide film, afluorine-containing resin film, a nylon film, a polymethyl methacrylatefilm, an acryl film, and a polyarylate film. A cyclopolyolefin resinsuch as ARTON (produced by JSR Co., Ltd.) or APEL produced by MitsuiKagaku Co., Ltd.) can be preferably used. The thickness of the substrateis preferably from 30 μm to 1 cm, and more preferably from 50 μm to 1000μm.

[0060] The layer containing the metal oxide, metal nitride or metaloxide nitride described above as a main component refers to a layercontaining the metal oxide, metal nitride or metal oxide nitride in anamount of not less than 50% by weight.

[0061] Examples of the metal oxide include silicon oxide, titaniumoxide, indium oxide, tin oxide, indium tin oxide (ITO), and alumina.Examples of the metal nitride include titanium nitride and siliconnitride. Examples of the metal oxide nitride include silicon oxidenitride, and titanium oxide nitride.

[0062] The silicon oxide is highly transparent, but has a poor gasbarrier property and a moisture penetrating property. It is preferredthat the silicon oxide layer preferably contains a nitrogen atom. Thesilicon oxide nitride and titanium oxide nitride are represented bySiOxNy and TiOxNy, respectively. When the nitrogen content in a layer isincreased, the gas barrier property is enhanced, but light transmittanceis lowered. When high light transmittance is necessary for the support,x and y preferably satisfy the following relationship:

0.4≦x/(x+y)≦0.8

[0063] The oxygen atom or nitrogen atom content can be measuredemploying XPS (ESCA LAB-200R produced by VIEWING ANGLE Scientific Co.,Ltd. in the same manner as a carbon atom content described later.

[0064] In the invention, the main component of the sealing layer ispreferably an oxide of aluminum, silicon, or titanium or an oxidenitride of silicon, or titanium, in view of low moisture penetrability.In the invention, when plural layers containing a metal oxide, a metaloxide nitride or a metal nitride are formed, at least one of the layershas a carbon content of from 1 to 40 atomic %. When plural layerscontaining a metal oxide, a metal oxide nitride or a metal nitride areformed, the plural layers are preferably those containing the same metaloxide, the same metal oxide nitride, or the same metal nitride buthaving a different carbon content.

[0065] As the organotin compound, organosilicon compound ororganotitanium compound described above, a metal hydride compound or ametal alkoxide compound is preferably used in view of handling, and themetal alkoxide compound is more preferably used, since it is notcorrosive, and generates no harmful gas nor causes contamination. Whenthe organotin compound, organosilicon compound or organotitaniumcompound described above is introduced into a discharge space or a spacebetween the electrodes. As the reactive gas for forming the sealinglayer, an organometallic compound and a metal hydride compound can beused. The compounds may be in the form of gas, liquid, or solid atordinary temperature and ordinary pressure. When they are gas atordinary temperature and ordinary pressure, they can be introduced inthe discharge space as they are. When they are liquid or solid, they aregasified by heating, or under reduced pressure or ultrasonic waveradiation, and used. The above compound may be diluted with anothersolvent. The solvents include an organic solvent such as methanol,ethanol, n-hexane or a mixture thereof. Since these solvents aredecomposed during discharge plasma treatment, their influence on thelayer formed on the substrate can be neglected.

[0066] A compound represented by formulae (1) through (4) describedbelow is preferred as the organometallic compound for forming a siliconoxide layer, since it is not corrosive, and generates no harmful gas norcauses contamination.

[0067] Formula (1)

[0068] wherein R₂₁ through R₂₆ independently represent a hydrogen atomor a monovalent substituent, and n1 represents a natural number.

[0069] Examples of the compound represented by formula (1) includehexamethyldisiloxane (HMDSO), tetramethyldisiloxane (TMDSO), and1,1,3,3,5,5-hexamethyltrisiloxane.

[0070] Formula (2)

[0071] wherein R₃₁ and R₃₂ independently represent a hydrogen atom or amonovalent substituent, and n2 represents a natural number.

[0072] Examples of the compound represented by formula (2) includehexamethylcyclotetrasiloxane, octamethylcyclotetrasiloxane, anddecamethylcyclopentanesiloxane.

(R₄₁)nSi(R₄₂)4−n   Formula (3)

[0073] wherein R₄₁ and R₄₂ independently represent a hydrogen atom or amonovalent substituent, and n represents an integer of from 0 to 3.

[0074] Examples of the organic compound represented by formula (3)include tetraethoxysilane (TEOS), methyltrimethoxysilane,methyltriethoxysilane, dimethyldimethoxysilane, dimethyldiethoxysilane,trimethylethoxysilane, ethyltrimethoxysilane, ethyltriethoxysilane,n-propyltrimethoxysilane, n-propyltriethoxysilane,n-butyltrimethoxysilane, i-butyltrimethoxysilane,n-hexyltrimethoxysilane, phenyltrimethoxysilane, vinyltrimethoxysilane,and vinyltriethoxysilane.

[0075] Formula (4)

[0076] wherein A represents a single bond or a divalent group, R₅₁through R₅₅ independently represent a hydrogen atom, a halogen atom, analkyl group, a cycloalkyl group, an alkenyl group, an aryl group, anaromatic heterocyclic group, an amino group or a cyano group, providedthat R₅₁ and R₅₂ or R₅₄ and R₅₅ may combine with each other to form aring.

[0077] In formula (4), A is preferably a single bond or a divalent grouphaving a carbon atom number of 1 to 3. R₅₄ and R₅₅ may combine with eachother to form a ring, and examples of the formed ring include a pyrrolering, a piperidine ring, a piperazine ring, and an imidazole ring. It ispreferred that R₅₁ through R₅₃ independently represent a hydrogen atom,a methyl group or an amino group.

[0078] Examples of the organic compound represented by formula (4)include aminomethyltrimethylsilane, dimethyldimethylaminosilane,dimethylaminotrimethylsilane, allylaminotrimethylsilane,diethylaminodimethylsilane, 1-trimethylsilylpyrrole,1-trimethylsilylpyrrolidine, isopropylaminomethyltrimethylsilane,diethylaminotrimethylsilane, anilinotrimethylsilane,2-piperidinoethyltrimethylsilane, 3-butylaminopropyltrimethylsilane,3-piperidinopropyltrimethylsilane, bis(dimethylamino)methylsilane,1-trimethylsilylimidazole, bis(ethylamino)dimethylsilane,bis(butylamino)dimethylsilane,2-aminoethylaminomethyldimethylphenylsilane,3-(4-methylpiperazinopropyl)trimethylsilane,dimethylphenylpiperazinomethylsilane,butyldimethyl-3-piperazinopropylsilane, dianilinodimethylsilane, andbis(dimethylamino)diphenylsilane.

[0079] A compound represented by formula (4) is preferably a compoundrepresented by formula (5).

[0080] Formula (5)

[0081] wherein R₆₁ through R₆₆ independently represent a hydrogen atom,a halogen atom, an alkyl group, a cycloalkyl group, an alkenyl group, anaryl group, or an aromatic heterocyclic group.

[0082] In formula (5), it is preferred that R₆₁ through R₆₆independently represent a hydrocarbon group having a carbon atom numberof 1 through 10, in view of easy gasification, and it is more preferredthat at least two of R₆₁ through R₆₃ are methyl groups and at least twoof R₆₄ through R₆₆ are methyl groups.

[0083] Examples of the organic compound represented by formula (5)include 1,1,3,3-tetramethyldisilazane,1,3-bis(chloromethyl)-1,1,3,3-tetramethyldisilazane,hexamethyldisilazane, and 1,3-divinyl-1,1,3,3-tetramethyldisilazane.

[0084] In order to form a tin oxide layer, for example, dibutyltindiacetate is used. Further, in order to form an aluminum oxide layer,for example, aluminum isopropoxide or tris(2,4-pentadionato)aluminum isused. In order to form a titanium oxide layer, for example, titaniumtetraisopropoxide is used.

[0085] Employing a mixed gas of an oxygen gas or a nitrogen gas in aspecific amount and the above organometallic compound, a layercontaining a metal atom such as silicon or tin and at least one of anitrogen atom and an oxygen atom.

[0086] In order to adjust a carbon content of the formed layer, ahydrogen gas may be further mixed in the mixed gas described above. Amixed gas in which inert gas belonging to a group XVIII of periodictable such as helium, neon, argon, krypton, xenon, or radon, preferablyhelium or argon, is mixed in the reactive gas is introduced in theatmospheric pressure plasma discharge generating apparatus (plasmagenerating apparatus) to form a layer. The content ratio of the inertgas to the reactive gas in the mixed gas used is 90.0 to 99.9% byvolume, although it differs due to properties of a layer formed.

[0087] The above-described mixed gas for forming a layer containing aspecific amount of for example, Si, O, N, and C will be explained below.

[0088] Explanation will be made regarding a silicon oxide nitride layerto have been formed employing a mixed gas of silazane and oxygen gas, inwhich x/(x+y) is not more than 0.8, and contains carbon in an amount offor example, 0.2 to 5% by weight. In this case, The Si and N in thelayer is derived from silazane.

[0089] The oxygen gas content of the mixed gas is preferably from 0.01to 5% by volume, and more preferably from 0.05 to 1% by volume.Considering reaction efficiency of oxygen gas and silazane, the contentratio (by mole) of oxygen gas to silazane in the mixed gas is set sothat it is 1 to 4 times the content ratio in the layer formed. Thus, theoxygen gas content and the content ratio of the oxygen gas to thesilazane are determined.

[0090] In forming a Si and N containing layer from silazane withoutusing oxygen, the content of gasified silazane in the mixed gas may befrom 0.2 to 1.5% by volume. Since a considerable amount of carbonremains in the layer, a part of the carbon is removed, employing a mixedgas containing a hydrogen gas in an amount of at most 2% by volume.

[0091] Besides the organosilicon compound, an inorganic silicon compoundcan be also used as the Si providing source.

[0092] As the oxygen providing source, ozone, carbon dioxide, or water(steam) may be used, besides an oxygen gas. As the nitrogen providingsource, ammonia or nitrogen oxides may be used, besides silazane or anitrogen gas.

[0093] The plasma layer formation apparatus used in the formation of thelayer in the invention will be explained employing FIGS. 1 to 6. In thefigures, a substrate F is a long-length film used as one example of asubstrate.

[0094] In the invention, the discharge plasma treatment preferably usedis carried out at atmospheric pressure or at approximately atmosphericpressure. Herein, approximately atmospheric pressure herein referred toimplies a pressure of 20 kPa to 110 kPa, and preferably 93 kPa to 104kPa.

[0095]FIG. 1 shows one embodiment of a plasma discharge treatmentchamber in the plasma layer formation apparatus. In the plasma dischargetreatment chamber 10 of FIG. 1, substrate F in the film form istransported while wound around roll electrode 25 rotating in thetransport direction (clockwise in FIG. 1). Plural fixed electrodes 26,which are fixed around roll electrode 25, are in the form of cylinderand opposed to the roll electrode 25.

[0096] The plasma discharge vessel 11, constituting the plasma dischargetreatment chamber 10, is preferably a vessel of pyrex (R) glass, but avessel of metal may be used if insulation from the electrodes issecured. For example, the vessel may be a vessel of aluminum orstainless steel laminated with a polyimide resin or a vessel of themetal which is thermally sprayed with ceramic to form an insulationlayer on the surface.

[0097] The substrate F, which has been wound around the roll electrode25, is pressed with nip rollers 15 and 16, transported into a dischargespace in the plasma discharge vessel 11 through guide roller 24,subjected to discharge plasma treatment, and then transported into thenext process through guide roller 27. Since discharge treatment in theinvention can be carried out at atmospheric pressure or approximatelyatmospheric pressure but not under vacuum condition, continuoustreatment as described above is possible, which can provide highproductive efficiency.

[0098] Blade 14 is provided at the vicinity of the nip rollers 15 and16, and prevents air accompanying the transported substrate F fromentering the plasma discharge vessel 11. The volume of the accompanyingair is preferably not more than 1% by volume and more preferably notmore than 0.1% by volume, based on the total volume of air in the plasmadischarge vessel 11, which can be attained by the nip rollers 15 and 16above.

[0099] A mixed gas used in the discharge plasma treatment is introducedinto the plasma discharge vessel 11 from supply port 12, and exhaustedfrom exhaust port 13 after discharge treatment.

[0100] Roll electrode 25 is a ground electrode, and opposed to voltageapplication electrodes, plural fixed electrodes 26. Discharge is inducedat a space between the roll electrode and the fixed electrodes, thereactive gas supplied to the space is excited by the discharge to be inthe state of plasma, and a long length substrate transported onto theroll electrode 25 is exposed to the reactive gas in the plasma state toform a layer resulting from the reactive gas on the substrate.

[0101] It is preferred that a layer formation rate be increased by highplasma density between the opposed electrodes, and high electric powerwith a high frequency be supplied in order to control the carbon contentof the layer formed. Typically, a high frequency voltage with afrequency of from 100 kHz to 150 MHz and preferably not less than 200kHz is preferably supplied. The power supplied across the space betweenthe opposed electrodes is preferably from 1 to 50 W/cm², and morepreferably not less than 2 W/cm².

[0102] The electrode surface area (cm²) to which voltage is appliedrefers to the surface area of the electrode at which discharge occurs.

[0103] The high frequency voltage applied to the electrodes may be acontinuous sine wave or a discontinuous pulsed wave. The sine wave ispreferred in providing high layer formation speed.

[0104] Such electrodes are preferably those in which a dielectric iscoated on the surface of a metal base material. A dielectric is coatedon at least one of fixed electrodes 26 and a roll electrode 25 opposedto each other, and preferably on both electrodes. The dielectric ispreferably an inorganic compound having a dielectric constant of from 6to 45.

[0105] When one of the electrodes 25 and 26 has a dielectric layer, theminimum space distance between the electrode and the dielectric layer ispreferably from 0.5 to 20 mm, and more preferably in the range of 1mm±0.5 mm, and when both electrodes described above have a dielectriclayer, the minimum space distance between both dielectric layers ispreferably from 0.5 to 20 mm, and more preferably in the range of 1mm±0.5 mm, in carrying out uniform discharge. The space distance betweenthe opposed electrodes is determined considering thickness of adielectric layer provided on the conductive metal base material, orapplied voltage level.

[0106] When a flexible substrate placed or transported between theelectrodes is exposed to plasma, employing as one of the electrodes aroll electrode capable of transporting the substrate while directlycontacting the roll electrode and surface-finishing the dielectric layerof the dielectric coated electrode by polishing treatment so as toobtain a surface roughness Rmax (according to JIS B 0601) of not morethan 10 μm, the dielectric layer thickness or the gap between theelectrodes can be maintained constant, and stable discharge can becarried out. Further, coverage of non-porous inorganic dielectric layerwith high precision and without strain or cracks due to thermalshrinkage difference or residual stress can provide an electrode withgreatly increased durability.

[0107] In preparing a dielectric coated electrode by coating adielectric layer on a metal base material, it is necessary that thedielectric layer surface be surface finished by polishing treatment asdescribed above and the difference in thermal expansion between thedielectric layer and the metal base material be reduced. Accordingly, ametal base material is preferably lined with an inorganic materiallayer, in which the foam content is controlled, as a stress absorbinglayer. The inorganic material for lining is preferably glass producedaccording to a melting method, which is known as enamel etc. It ispreferred that the foam content of the lowest layer which contacts theconductive metal base material is 20 to 30% by volume, and the foamcontent of the layer or layers provided on the lowest layer is not morethan 5% by volume, which provides a good electrode with high density andwithout cracks.

[0108] Another preferred method for coating a dielectric on a metal basematerial is a method in which a ceramic is thermally splayed on themetal base material to form a ceramic layer with a void content of notmore than 10% by volume, and sealed with an inorganic material capableof being hardened by a sol-gel reaction. In order to accelerate the solgel reaction, heat hardening or UV irradiation is preferably carriedout. Sealing treatment, in which coating of diluted sealing solution andhardening are alternately repeated several times, provides an electrodewith improved inorganic property, with high density and without anydeterioration.

[0109]FIG. 2(a) and FIG. 2(b) show roll electrode 25 c and rollelectrode 25C, respectively, as examples of roll electrode 25.

[0110] As is shown in FIG. 2(a), roll electrode 25 c, which is a groundelectrode, is an electrode in which a conductive base roll 25 a such asa metal roll is coated with ceramic to form a ceramic dielectric layer25 b as a dielectric layer, the coating being carried out by thermallyspraying ceramic on the base roll to form a ceramic layer, and sealingthe ceramic layer with sealing materials such as inorganic compounds.The roll electrode is prepared to have a ceramic dielectric layer with athickness of 1 mm and a roll diameter of 200φ, and is grounded. Theceramic material used for thermal spraying is preferably alumina,silicon nitride, and more preferably alumina in view of easyprocessability.

[0111] Further, as is shown in the roll electrode 25C of FIG. 2(b), theroll electrode may be an electrode in which a conductive base roll 25Asuch as a metal roll is lining coated with inorganic materials to form alined dielectric layer 25B as a dielectric layer. Materials for liningare preferably silicate glass, borate glass, phosphate glass, germanateglass, tellurite glass, aluminate glass, and vanadate glass. Amongthese, borate glass is more preferably used in view of easyprocessability.

[0112] Examples of a metal used in the conductive metal base roll 25 aor 25A include metals such as silver, platinum, stainless steel,aluminum, and iron. Stainless steel is preferable in view ofprocessability.

[0113] In one embodiment carried out in the invention, a base roll forthe roll electrode employs a stainless steel jacket roll having thereina cooling means (not illustrated in the Figs.) employing chilled water.

[0114] The roll electrodes 25 c and 25C (similarly, roll electrode 25)are set to rotate around the axes 25 d and 25D, respectively, by adriving system not illustrated.

[0115]FIG. 3(a) shows a perspective view of fixed electrode 26. Thefixed electrode is not limited to a cylindrical form, an may be in theprismatic form as shown in fixed electrode 36 of FIG. 3 (b) . Theprismatic electrode has a discharge area larger than the cylindricalelectrode 26, and is preferably used according to properties of thelayer formed.

[0116] The fixed electrodes 26 and 36 have the same constitution as thatof the roll electrode 25 c or 25C described above. That is, in the samemanner as in roll electrode 25 (25 c and 25C) above, dielectric layers26 b and 36 b are coated on hollow stainless steel pipes 26 a and 36 a,respectively, and the resulting electrodes are constructed so as to becooled with chilled water during discharge. The dielectric layers 26 band 36 b may be a layer formed by ceramic thermal spraying or a layerformed by lining.

[0117] In an example as shown in FIG. 1, fixed electrodes having adielectric layer are prepared to give a roll diameter of 12φ or 15φ, andfourteen of the fixed electrodes are arranged around the circumferenceof the roll electrode described above.

[0118]FIG. 4 shows a plasma discharge chamber 30 in which the fixedprismatic electrode 36 as shown in FIG. 3(b) is arranged around thecircumference of the roll electrode 25. The numerical numbers shown inFIG. 4 mean the same as denoted in FIG. 1.

[0119]FIG. 5 shows a schematic view of one embodiment of the plasmalayer formation apparatus used in the invention. In FIG. 5, the plasmalayer formation apparatus 50 is equipped with plasma discharge chamber30 shown in FIG. 4. In the plasma layer formation apparatus 50, a gasgenerating device 51, a power source 41, and an electrode cooling device55 and so on are further provided in addition to plasma dischargechamber 30. The electrode cooling device 55 is comprised of a tank 57containing a cooling agent and a pump 56. As the cooling agent,insulating materials such as distilled water and oil are used. The gapdistance between the opposed electrodes in the plasma discharge chamber30 shown in FIG. 5 is, for example, approximately 1 mm.

[0120] A mixed gas generated in the gas generating device 51 isintroduced from supply port 12 in a controlled amount into the plasmadischarge chamber 30, in which roll electrode 25 and fixed electrode 36are arranged at a predetermined position, whereby the plasma dischargevessel 11 is charged with the mixed gas, and thereafter, the unnecessarygas is exhausted from the exhaust port 13.

[0121] Subsequently, the roll electrode 25 being grounded, voltage isapplied to electrodes 36 by power source 41 to generate dischargeplasma. A flexible substrate F is supplied from stock roll FF throughrolls 54, and transported to a gap between the electrodes in the plasmadischarge chamber 30 through guide roller 24 so that the one side of thesubstrate contacts the surface of the roll electrode 25. Duringtransporting, the flexible substrate F is subjected to discharge plasmatreatment, and then transported to the next processing through guideroller 27. In the above, only the surface of the flexible substrate Fopposite the surface contacting the roll electrode is subjected todischarge treatment.

[0122] In order to minimize an adverse effect due to high temperatureduring the discharge plasma treatment, the substrate temperature iscooled to a temperature of preferably from ordinary temperature (15 to25° C.) to less than 200° C., and more preferably from ordinarytemperature to 100° C., optionally employing an electrode cooling means55. Numerical numbers 14, 15 and 16 mean the same as in FIG. 1.

[0123]FIG. 6 shows a schematic view of a plasma layer formationapparatus 60 used in the invention. The plasma layer formation apparatus60 is used when a layer is formed on a substrate which cannot beprovided at the space between the opposed electrodes, for example, asubstrate 61 having a great thickness, wherein a reactive gas to havebeen in a plasma state is jetted onto the substrate to form a layer onthe substrate.

[0124] In the plasma layer formation apparatus 60 of FIG. 6, numericalnumbers 35 a, 35 b and 65 represents a dielectric layer, a metal basematerial, and a power source, respectively. A mixed gas comprised of areactive gas and inert gas is introduced into a slit formed between theopposed electrodes in which a dielectric layer 35 a is coated with ametal base material 35 b. The introduced reactive gas is excited to aplasma state by applying voltage to the electrodes, and the gas in theplasma state is jetted onto the substrate 61 to form a layer on thesubstrate 61.

[0125] Power source 41 of FIG. 5 or power source 65 of FIG. 6, which isused for forming the layer in the invention, is not specificallylimited. As the power sources, impulse high frequency power source(continuous mode, 100 kHz) produced by Heiden Kenkyusho, a highfrequency power source (200 kHz) produced by Pearl Kogyo Co., Ltd., ahigh frequency power source (800 kHz) produced by Pearl Kogyo Co., Ltd.,a high frequency power source (13.56 MHz) produced by Nippon Denshi Co.,Ltd., and a high frequency power source (150 MHz) produced by PearlKogyo Co., Ltd. can be used.

[0126] The sealing layer and/or polymer layer in the invention can beformed according to the atmospheric pressure plasma method, employingthe plasma layer formation apparatus as described above.

[0127] The polymer layer contains a polymeric compound as a maincomponent. The polymeric compound is obtained by polymerization of amonomer comprising a vinyl compound or an acetylene compound. When thepolymer layer in the invention is formed according to the atmosphericpressure plasma method, a vinyl compound having a vinyl group or anacetylene compound having an acetylenyl group is preferably used as areactive gas. Examples of the vinyl compound having a vinyl group or theacetylene compound acetylenyl group include methyl methacrylate, ethylacrylate, vinyl acetate, styrene, iso-propyl vinyl ether, and acetylene.When the polymer layer is formed, these compounds can be plasma treatedunder layer formation conditions such that they are polymerized withoutbeing decomposed. The frequency of the power source is preferably from 3to 150 MHz.

[0128] The thickness of the sealing layer in the invention can beadjusted, increasing the plasma treatment time, or repeating plasmatreatment. The layer thickness capable of substantially preventingmoisture from penetrating in the layer is preferably not less than 50nm, and more preferably not less than 100 nm. The thick sealing layerprovides an excellent moisture resistance, but since a too thick sealinglayer shows low stress relaxation, the thickness thereof is preferablynot more than 2000 nm. When plural sealing layers are formed, it ispreferred that each sealing layer have the thickness range definedabove.

[0129] The thickness of the polymer layer in the invention is preferablyfrom 50 to 2000 nm, and more preferably from 100 to 1000 nm, in that thesealing layer does not peel from the substrate or has good stressrelaxation. When plural polymer layers are formed, it is preferred thateach polymer layer have the thickness range defined above.

[0130] The support of the invention comprising the sealing layer and thepolymer layer will be explained below.

[0131] The support of the invention comprises a resin substrate, andprovided thereon, a sealing layer having a thickness of preferably notless than 100 nm, and more preferably not less than 200 nm, and apolymer layer adjacent to the sealing layer in that order. When thesupport is folded, the sealing layer is likely to peel off from thesubstrate, however, stress relaxation of the polymer layer prevents thesealing layer from peeling off. Further, the polymer layer can providelow moisture penetration.

[0132]FIG. 7 shows a sectional view of the support comprising the layerstructure described above. The support has a resin substrate 100, andprovided thereon, a sealing layer 101 and a polymer layer 102 in thatorder, the polymer layer being adjacent to the sealing layer. Thethickness of both layers may be the same or different.

[0133] The preferred embodiment of the invention is a support in whichthe polymer layer 102 are provided closer to the substrate 100 than thesealing layer 101, wherein the polymer layer substantially preventsmoisture from penetrating into the layer, and increases adhesion of thesealing layer 101, which provides a moisture sealing property to thesupport, to the substrate.

[0134]FIG. 8 shows a sectional view of one embodiment of the supporthaving two or more of the layer structure described above. The supporthas a resin substrate 100, and provided thereon, a sealing layer 101, apolymer layer 102, a sealing layer 101, and a polymer layer 102 in thatorder. The two sealing layers 101 and the two polymer layers 102 neednot have the same composition or the same layer thickness, respectively.In order to obtain the support having such plural layer structuresaccording to the atmospheric plasma method, the substrate can be plasmatreated in the plasma layer formation apparatus described above severaltimes.

[0135] The support of the invention, even when a resin substrate is usedas a flexible substrate, can not only maintain the flexibility which theflexible resin has, but can seal moisture contained in the resinsubstrate or water vapor penetrating in the resin substrate due to awater sealing property which the sealing layer has. Accordingly, sincethe sealed inner space of the display can maintain the humidity to below, a flexible display prepared by forming an organicelectroluminescence (EL) element on such a support and sealing it with aflexible material such as a film, preferably the same support as above,can solve problem that properties of the organic electroluminescenceelement which is sensitive to moisture gradually degrade due to themoisture contained in a sealing agent or the support, which greatlylengthen its life.

[0136] In the invention, at least one of laminated layers comprising apolymer layer and a sealing layer is formed by an atmospheric pressureplasma method. The layer formation methods in the invention include amethod in which all the layers are formed by an atmospheric pressureplasma method, and a method in which the sealing layer is formed by anatmospheric pressure plasma method, and a polymer layer is formed by avacuum deposition method or other layer formation methods.

[0137] The other layer formation methods above are may be any methodsincluding a sol gel method in which a coating solution is coated, avacuum deposition method, a sputtering method, and a CVD method(chemical deposition).

[0138] The organic electroluminescence element of the invention,employing the support of the invention, will be detailed below.

[0139] In the invention, the organic electroluminescence element has astructure in which a light emission layer is provided between a pair ofelectrodes, an anode and a cathode. The light emission layer hereinbroadly refers to a layer emitting light when electric current issupplied to the electrode comprised of the cathode and the anode.Typically, the light emission layer is a layer containing an organiccompound emitting light when electric current is supplied to anelectrode comprised of a cathode and an anode.

[0140] The organic EL element of the invention has a structure in whicha hole injecting layer, an electron injecting layer, a hole transportinglayer, and an electron transporting layer, in addition to the lightemission layer, are optionally provided between the cathode and theanode. Further, the organic EL element may have a protective layer.

[0141] In concrete, the following structures are included.

[0142] (i) Anode/Light emission layer/Cathode

[0143] (ii) Anode/Hole injecting layer/Light emission layer/Cathode

[0144] (iii) Anode/Light emission layer/Electron injecting layer/Cathode

[0145] (iv) Anode/Hole injecting layer/Light emission layer/Electroninjecting layer/Cathode

[0146] (v) Anode/Hole injecting layer/Hole transporting layer/Lightemission layer/Electron transporting layer/Electron injectinglayer/Cathode

[0147] Further, a cathode buffering layer (for example, a lithiumfluoride layer) may be inserted between the electron injecting layer andthe cathode, and an anode buffering layer (for example, a copperphthalocyanine layer) may be inserted between the hole injecting layerand the anode.

[0148] The light emission layer may comprise a hole injecting layer, anelectron injecting layer, a hole transporting layer, or an electrontransporting layer. That is, the light emission layer may have at leastone of the following functions: (1) an injecting function capable ofinjecting holes from an anode or a hole injecting layer and injectingelectrons from a cathode or an electron injecting layer by applicationof electric field, (2) a transporting function capable of transportingthe injected charges (holes and electrons) by application of electricfield, and (3) an emission function capable of providing the field ofrecombination of holes and electrons which leads to light emission. Inthe above case, apart from the light emission layer, at least one of thehole injecting layer, the electron injecting layer, the holetransporting layer, and the electron transporting layer is notnecessary. Further, a hole injecting layer, an electron injecting layer,a hole transporting layer, and an electron transporting layer beingadded with a light emission compound, they may be given a function of alight emission layer. In the light emission layer, ease with which holesare injected may be different from ease with which electrons areinjected, and a hole or electron transporting ability represented by itsmobility may be different. However, it is preferred that the lightemission layer has a function of transporting at least one of the holesand electrons.

[0149] Light emission materials used in the light emission layer are notspecifically limited, and known materials used in the conventionalorganic EL element can be used. Such a light emission material is mainlyan organic compound, and examples of the organic compound includecompounds disclosed on pages 17 through 26 in “Macromol. Symp.”, vol.125, according to desired color tones.

[0150] The light emission materials may have a hole injecting functionor a electron injecting function, in addition to the light emissionfunction. Most of hole injecting materials or electron injectingmaterials can be also used as the light emission materials.

[0151] The light emission materials may be a polymer such asp-polyphenylenevinylene or polyfluorene, and a polymer in which theabove light emission material is incorporated in the polymer side chainor in the polymer main chain.

[0152] The light emission layer may contain a dopant (a guestsubstance), and as the dopant can be used a compound selected from theknown dopants used in the conventional El element.

[0153] Examples of the dopant include quinacridone, DCM, coumarinderivatives, rubrene, decacyclene, pyrazoline derivatives, squaliriumderivatives and europium complexes. Further, examples of the dopantinclude iridium complexes (for example, those disclosed in JapanesePatent O.P.I. Publication No. 2001-248759 or compounds represented byformulas on pages 16 through 18 of WO 0070655, for example,tris(2-phenylpyridine)iridium etc.), osmium complexes or platinumcomplexes, for example, 2,3,7,8,12,13,17,18-octaethyl-21H,23H-porphyrinplatinum complex.

[0154] As methods of forming a light emission layer employing thecompounds mentioned above, there are known methods for forming a thinlayer such as a deposition method, a spin-coat method, a casting methodand an LB method. The light emission layer is preferably a moleculardeposit layer. The molecular deposit layer herein refers to a layerformed by deposition of the above compounds in a gaseous state, or bysolidification of the above compounds in a melted state or a liquefiedstate. The molecular deposit layer is distinguished from a thin layer(molecular cumulation layer) formed by an LB method in structure, forexample, an aggregated structure or a higher order structure, or infunction. The function difference results from the structural differencebetween them.

[0155] Further, the light emission layer can be formed by the methodsuch as that described in Japanese Patent O.P.I. Publication No.57-51781, in which the above light emission material is dissolved in asolvent together with a binder such as a resin, and the thus obtainedsolution is coated on a base to form a thin layer by a method such as aspin-coat method. The thickness of the thus formed light emission layeris not specially limited, and is optionally selected, but the thicknessis ordinarily within the range of from 5 nm to 5 μm.

[0156] The hole injecting material for the hole injecting layer may beeither an organic substance or an inorganic substance as long as it hasa hole injecting ability or an ability to form a barrier to electron.Examples of the hole injecting material include a triazole derivative,an oxadiazole derivative, an imidazole derivative, a polyarylalkanederivative, a pyrazoline derivative and a pyrazolone derivative, aphenylenediamine derivative, an arylamine derivative, an aminosubstituted chalcone derivative, an oxazole derivative, a styrylanthracene derivative, a fluorenone derivative, a hydrazone derivative,a stilbene derivative, a silazane derivative, an aniline copolymer, andan electroconductive oligomer, particularly a thiophene oligomer. As thehole injecting material, those described above can be used, but aporphyrin compound, an aromatic tertiary amine compound, or astyrylamine compound is preferably used, and an aromatic tertiary aminecompound is more preferably used.

[0157] Typical examples of the aromatic tertiary amine compound andstyrylamine compound include N,N,N′,N′-tetraphenyl-4,4′-diaminophenyl,N,N′-diphenyl-N,N′-bis(3-methylphenyl)-[1,1′-biphenyl]-4,4′-diamine(TPD), 2,2-bis(4-di-p-tolylaminophenyl)propane,1,1-bis(4-di-p-tolylaminophenyl)cyclohexane,N,N,N′,N′-tetra-p-tolyl-4,4′-diaminobiphenyl,1,1-bis(4-di-p-tolylaminophenyl)-4-phenylcyclohexane,bis(4-dimethylamino-2-methylphenyl)-phenylmethane,bis(4-di-p-tolylaminophenyl)phenylmethane,N,N′-diphenyl-N,N′-di(4-methoxyphenyl)-4,4′-diaminobiphenyl,N,N,N′,N′-tetraphenyl-4,4′-diaminodiphenylether,4,4′-bis(diphenylamino)quardriphenyl, N,N,N-tri(p-tolyl)amine,4-(di-p-tolylamino)-4′-[4-(di-p-tolylamino)styryl]stilbene,4-N,N-diphenylamino-(2-diphenylvinyl)benzene,3-methoxy-4′-N,N-diphenylaminostilbene, N-phenylcarbazole, compoundsdescribed in U.S. Pat. No. 5,061,569 which have two condensed aromaticrings in the molecule thereof such as4,4′-bis[N-(1-naphthyl)-N-phenylamino]biphenyl (NPD), and compoundsdescribed in Japanese Patent O.P.I. Publication No. 4-308688 such as4,4′,4″-tris[N-(3-methylphenyl)-N-phenylamino]-triphenylamine (MTDATA)in which three triphenylamine units are bonded in a starburst form.

[0158] As the hole injecting material, inorganic compounds such as p-Siand p-SiC are usable. The hole injecting layer can be formed layeringthe hole injecting material described above according to a known methodsuch as a vacuum deposition method, a spin coat method, a castingmethod, an ink jet method, and an LB method. The thickness of the holeinjecting layer is not specifically limited, but is ordinarily from 5 nmto 5 μm. The hole injecting layer may be composed of a single layercomprising one, or two or more of the materials mentioned above, or ofplural layers the composition of which may be the same or different.

[0159] The electron injecting layer may be a layer having a function oftransporting electrons injected to the cathode to the light emissionlayer. The material for the electron injecting layer may be selectedfrom known compounds. Examples of the material used in the electroninjecting layer (hereinafter referred to also as electron injectingmaterial) include a nitro-substituted fluorene derivative, adiphenylquinone derivative, a thiopyran dioxide derivative, atetracarboxylic acid anhydride such as naphthalene tetracarboxylic acidanhydride or perylene tetracarboxylic acid anhydride, a carbodiimide, afluolenylidenemethane derivative, an anthraquinodimethane an anthronederivative, and an oxadiazole derivative. Various electron transportingcompounds described in Japanese Patent O.P.I. Publication No. 59-194393is disclosed as compounds for forming a light emission, but it has beenproved that these can be also used as the electron injecting material.Moreover, a thiadiazole derivative which is formed by substituting theoxygen atom in the oxadiazole ring of the foregoing oxadiazolederivative with a sulfur atom, and a quinoxaline derivative having aquinoxaline ring known as an electron withdrawing group are usable asthe electron injecting material. A metal complex of an 8-quinolinolderivative such as tris(8-quinolinolato)aluminum (Alq₃),tris(5,7-dichloro-8-quinolinolato)aluminum,tris(5,7-dibromo-8-quinolinolato)aluminum,tris(2-methyl-8-quinolinolato)aluminum,tris(5-methyl-8-quinolinolato)aluminum, or bis(8-quinolinolato)zinc(Znq₂), and a metal complex formed by replacing the center metal of theforegoing complexes with another metal atom such as In, Mg, Cu, Ca, Sn,Ga or Pb can be used as the electron injecting material. Furthermore, ametal free or metal-containing phthalocyanine, and a derivative thereof,in which the molecular terminal is replaced by a substituent such as analkyl group or a sulfonic acid group, are also preferably used as theelectron injecting material. The distyrylpyrazine derivative exemplifiedas a material for a light emission layer may preferably be employed asthe electron injecting material. An inorganic semiconductor such as n-Siand n-SiC may also be used as the electron injecting material in asimilar way as in the hole injecting layer.

[0160] The electron injecting layer can be formed by layering thecompounds described above by a known method such as a vacuum depositionmethod, a spin coat method, a casting method and an LB method. Thethickness of the electron injecting layer is not specifically limited,but is ordinarily from 5 nm to 5 μm. The electron injecting layer may becomposed of a single layer comprising one or two or more of the electroninjecting material mentioned above, or of plural layers comprising thesame composition or different composition.

[0161] A buffering layer (an electrode interface layer) may be providedbetween the anode and the light emission layer or the hole injectinglayer, or between the cathode and the light emission layer or theelectron injecting layer.

[0162] The buffering layer is a layer provided between the electrode andan organic layer in order to reduce the driving voltage or to improve oflight emission efficiency. As the buffering layer there are an anodebuffering layer and a cathode buffering layer, which are described indetail in “Electrode Material” page 123, Div. 2 Chapter 2 of “Organic ELelement and its frontier of industrialization” (published by NTSCorporation, Nov. 30, 1998).

[0163] The anode buffering layer is described in detail in JapanesePatent O.P.I. Publication Nos. 9-45479, 9-260062, and 8-288069 etc., andits examples include a phthalocyanine buffering layer represented by acopper phthalocyanine layer, an oxide buffering layer represented by avanadium oxide layer, an amorphous carbon buffering layer, a polymerbuffering layer employing an electroconductive polymer such aspolyaniline (emeraldine), and polythiophene, etc.

[0164] The cathode buffering layer is described in detail in JapanesePatent O.P.I. Publication Nos. 6-325871, 9-17574, and 9-74586, etc., andits examples include a metal buffering layer represented by a strontiumor aluminum layer, an alkali metal compound buffering layer representedby a lithium fluoride layer, an alkali earth metal compound bufferinglayer represented by a magnesium fluoride layer, and an oxide bufferinglayer represented by an aluminum oxide.

[0165] The buffering layer is preferably very thin and has a thicknessof preferably from 0.1 to 100 nm depending on kinds of the materialused.

[0166] A layer having another function may be provided if necessary inaddition to the fundamental component layers as described above, forexample a hole blocking layer may be added as described in JapanesePatent O.P.I. Publication Nos. 11-204258, and 11-204359, and on page 237of “Organic EL element and its frontier of industrialization” (publishedby NTS Corporation, Nov. 30, 1998).

[0167] At least one of the cathode buffering layer and anode bufferinglayer may contain the compound in the invention, and function as a lightemission layer.

[0168] As the electrode material for the anode of the organic ELelement, a metal, an alloy, or an electroconductive compound each havinga high working function (not less than 4 eV), and mixture thereof arepreferably used. Concrete examples of such an electrode material includea metal such as Au, and a transparent electroconductive material such asCuI, indium tin oxide (ITO), SnO₂, or ZnO.

[0169] As the anode, a thin layer of the electrode material describedabove is formed according to a depositing or sputtering method, in whichthe layer may be formed into a desired pattern according tophotolithography, or in which when required precision of the pattern isnot so high (not less than 100 μm), the layer may be formed into adesired pattern through a mask having the pattern. When light is emittedthrough the anode, the transmittance of the anode is preferably 10% ormore, and the sheet resistivity of the anode is preferably not more thanseveral hundred Ω/□. The thickness of the layer is ordinarily within therange of from 10 nm to 1 μm, and preferably from 10 to 200 nm, althoughit may vary due to kinds of materials used.

[0170] On the other hand, as the electrode material for the cathode ofthe organic EL element, a metal (also referred to as an electroninjecting metal), an alloy, and an electroconductive compound eachhaving a low working function (not more than 4 eV), and a mixturethereof is used. Concrete examples of such an electrode material includesodium, sodium-potassium alloy, magnesium, lithium, a magnesium/coppermixture, a magnesium/silver mixture, a magnesium/aluminum mixture,magnesium/indium mixture, an aluminum/aluminum oxide (Al₂O₃) mixture,indium, a lithium/aluminum mixture, and a rare-earth metal. Among them,a mixture of an electron injecting metal and a metal with a workingfunction higher than that of the electron injecting metal, such as amagnesium/silver mixture, a magnesium/aluminum mixture, amagnesium/indium mixture, an aluminum/aluminum oxide (Al₂O₃) mixture ora lithium/aluminum mixture, is suitable from the view point of theelectron injecting ability and resistance to oxidation. The cathode canbe prepared forming a thin layer of such an electrode material accordingto a method such as a deposition or sputtering method. The sheetresistivity as the cathode is preferably not more than several hundredΩ/□, and the thickness of the cathode is ordinarily from 10 nm to 1 μm,and preferably from 50 to 200 nm. It is preferable in increasing thelight emission efficiency that either the anode or the cathode of theorganic EL element is transparent or semi-transparent.

[0171] Next, the suitable embodiment of the organic EL element of theinvention, which comprises the structure anode/hole injectinglayer/light emission layer/electron injecting layer/cathode and issealed employing the support of the invention, will be explained.

[0172]FIG. 9 shows a sectional view of one embodiment of the EL elementof the invention employing the support of the invention. The EL elementhas a transparent support 1 and a support 5 (hereinafter referred toalso as counter support 5) opposed to the support 1. The support 1 isthe support of the invention shown in FIG. 8, which comprises a plasticsheet substrate 100 comprised of a resin such as polyester,polyacrylate, polycarbonate, polysulfone, or polyetherketone, andprovided thereon, a polymer layer and a sealing layer which have beenformed by atmospheric pressure plasma discharge treatment.

[0173] An organic EL layer is provided on the support 1, and pluralanodes 2 are provided in parallel with each other on the layer 101 ofthe support 1 comprising the sheet 100 and provided thereon, a polymerlayer 102, a sealing layer 101, a polymer layer 102, and a sealing layer101 in that order (laminate layer 7). A thin layer of a desiredelectrode material such as an anode material is formed by a depositionor sputtering method so that the thickness of the layer is not more than1 μm, and preferably within the range of from 10 to 200 nm to prepare ananode 2. As the electrode material for the anode of the organic ELelement are used a metal, an alloy or an electroconductive compound eachhaving a high working function (not less than 4 eV), and a mixturethereof, for example, a metal such as Au and a transparentelectroconductive material such as CuI, indium tin oxide (ITO), indiumzinc oxide (IZO), SnO₂ or ZnO.

[0174] Next, an organic EL layer 3 is formed on the anode 2, whereinalthough not illustrated, a hole injecting layer, a light emissionlayer, and an electron injecting layer are formed on the anode,employing the materials as described above.

[0175] Subsequently, a thin layer of a cathode material selected fromthe materials described above is formed by a deposition or sputteringmethod to prepare a cathode 4 on the organic EL layer 3. As describedabove, it is preferable in increasing the light emission efficiency thateither the anode or the cathode of the organic EL element be transparentor semi-transparent.

[0176] For formation of each layer of the organic EL element 3, a vacuumdeposition method is preferably used even though a spin coating method,a casting method and a deposition method can be used. The vacuumdeposition method is preferable since a uniform layer can be formed anda pinhole is formed with difficulty. Although conditions of the vacuumdeposition are different due to kinds of materials used or due to anintended crystalline or association structure of the moleculardeposition layer, the vacuum deposition is preferably carried out at aboat temperature of from 50° C. to 450° C., at a vacuum degree of from10⁻⁶ to 10⁻³ Pa, at a deposition speed of from 0.01 to 50 nm/second, andat a substrate temperature of from −50 to 300° C., to form a layerthickness of from 5 nm to 5 μm.

[0177] After formation of these layers, a thin layer of a material forcathode is provided thereon by, for example, a deposition method orsputtering method so that the thickness is not more than 1 μm, andpreferably from 50 to 200 nm, to form a cathode. Thus a desired organicEL element is obtained.

[0178] It is preferred that the layers from the hole injecting layer tothe cathode are continuously formed under one time of vacuuming toprepare the organic EL element. Further, the organic EL element can beprepared in the reverse order, in which the cathode, the electroninjecting layer, the light emission layer, hole injecting layer, and theanode are formed in that order. Light emission can be observed when adirect current with a voltage of from about 5 to 40 V is applied to thethus prepared organic EL element so that the polarity of the anode ispositive and that of the cathode is negative. When the voltage isapplied in the reverse polarity, no current is generated and light isnot emitted at all. When an alternating voltage is applied, light isemitted only when the polarity of the anode is positive and that of thecathode is negative. The shape of the wave of the alternating currentmay be optionally selected.

[0179] A protective layer may be provided on the surface of the organicEL layer 3 including the cathode 4. The inorganic protective layer iscomprised of for example, a dispersion in which SiO₂ is dispersed inCeO₂. The inorganic protective layer may be formed according to asputtering method, an ion plating method, or a deposition method. Thethickness of the inorganic protective layer is 0.1 to 10000 Å, andpreferably 50 to 1000 Å. After the cathode 4 is formed on the organic ELlayer, the inorganic protective layer is successively formed on thecathode under vacuum, which is not taken out from a vacuum chamber, orafter the cathode 4 is formed on the organic EL layer, the resultingmaterial is removed from a vacuum chamber, transported in a nitrogen orinert gas atmosphere, and then the inorganic protective layer is formedon the cathode under vacuum.

[0180] The organic EL layer 3 including cathode 4 is covered with asupport 5 as a counter support, comprising a substrate 100 and alaminate layer 8 comprised of a polymer layer 102, a sealing layer 101,a polymer layer 102, and a sealing layer 101 provided on the substratein that order, and sealed.

[0181] The sealing is carried out as follows. A sealing agent layer isprovided in the frame form on the peripheral portions of the surface ofthe counter support 5 (the surface facing the transparent support 1)through a coating method or a transfer method, and the counter support 5is adhered to the transparent support 1 through the sealing agent layer.Examples of the sealing agent include a heat curable epoxy resin, aphoto curable epoxy resin and an epoxy resin comprising amicro-encapsulated initiator capable of being hardened at ordinarytemperature by application of pressure. In this case, openings (notillustrated) for exhausting air are provided at specific portions of thesealing agent layer to complete the sealing. The openings are closedwith the above epoxy resins or a UV hardenable resin under reducedpressure (at a pressure of preferably not more than 1.33×10⁻² Mpa) orunder a nitrogen gas or inert gas atmosphere.

[0182] The above epoxy resin comprises, as a main component, a resin ofbisphenol A type, bisphenol F type, bisphenol AD type, bisphenol S type,xylenol type, phenol novolak type, cresol novolak type, polyfunctionaltype, tetraphenyrolmethane type, polyethylene glycol type, polypropyleneglycol type, hexane diol type, trimethylol propane type, propylene oxidebisphenol A type, hydrogenated bisphenol A type, or their mixture type.When a sealing agent 6 is formed by transfer, a sealing agent ispreferably in the film form.

[0183] The counter substrate 100 may be comprised of glass, resin,ceramic, metal, a metal compound, or their composite. The countersubstrate is preferably a substrate with a thickness of not less than 1μm having a water vapor penetration of not less than 1 g/m²·1 atm·24 hr(at 25° C.) in the test carried out according to JIS Z-0208. Such asubstrate may be used as the counter substrate.

[0184] In the invention, a material (for example, barium oxide)absorbing or reacting with moisture can be enclosed in the abovesupport.

[0185] In the organic EL element as described above, the transparentsupport 1 is adhered to the counter support 5 through a sealing material6 in the frame form. The organic El element provided on the transparentsupport 1 and cathode 4, etc. can be covered with the counter support 5and the sealing material 6. Accordingly, the light emission layer can beenclosed at low humidity in the organic El element, and penetration ofmoisture through the support can be restrained, whereby the organic ELdisplay can be obtained in which humidity resistance is improved andgeneration or growth of dark spots is restrained.

[0186]FIG. 10 shows a schematic view of another embodiment of theorganic EL element of the invention. The numerical numbers shown in FIG.10 mean the same as in FIG. 9.

[0187]FIG. 11 shows a schematic view of still another embodiment of theorganic EL element of the invention employing the support of theinvention. The numerical numbers shown in FIG. 11 mean the same as inFIG. 9.

[0188] The constitutions of the support and the organic EL elementdescribed above are the embodiments of the present invention, but thepresent invention is not limited thereto.

EXAMPLES

[0189] The present invention will be explained in the followingexamples, but is not limited thereto.

Example 1

[0190] (Preparation of Support A of the Invention)

[0191] A methyl methacrylate-vinyl acetate copolymer layer as a polymerlayer and an alumina layer as a sealing layer (metal oxide layer) wereformed on a 100 μm thick PET (polyethylene terephthalate) filmsubstrate, employing a plasma layer formation apparatus as shown in FIG.1, so that four layers, i.e., a first polymer layer, a first sealinglayer (aluminum oxide layer), a second polymer layer, and a secondsealing layer (aluminum oxide layer) were formed on the substrate inthat order. Thus, support A was obtained.

[0192] Herein, the gas used and power supplied were as follows:(Preparation of polymer layer) Composition of mixed gas used Inert gas:argon 99% by volume Reactive gas: methyl methacrylate 0.5% by volume(gasified by bubbled with argon at 90° C.) Reactive gas: vinyl acetate0.5% by volume (gasified by bubbled with argon at 60° C.)

[0193] Power Supplied:

[0194] A power of 5 W/cm² with a frequency of 100 kHz was supplied.(Preparation of sealing layer) Composition of mixed gas used Inert gas:argon 98.75% by volume Reactive gas: oxygen 1.0% by volume Reactive gas:Aluminum isopropoxide 0.25% by volume (gasified by bubbled with argon at160° C.)

[0195] Power Supplied:

[0196] A power of 5 W/cm² with a frequency of 13.56 MHz was supplied.

Example 2

[0197] (Preparation of Support B of the Invention)

[0198] Support B was obtained in the same manner as in Example 1, exceptthat six layers, a first polymer layer, a first sealing layer (aluminumoxide layer), a second polymer layer, a second sealing layer (aluminumoxide layer), a third polymer layer, and a third sealing layer (aluminumoxide layer) were formed on the PET film substrate in that order.

Example 3

[0199] (Preparation of Support C of the Invention)

[0200] Support C was obtained in the same manner as in Example 1, exceptthat ten layers, a first polymer layer, a first sealing layer (aluminumoxide layer), a second polymer layer, a second sealing layer (aluminumoxide layer), a third polymer layer, a third sealing layer (aluminumoxide layer), a fourth polymer layer, a fourth sealing layer (aluminumoxide layer), a fifth polymer layer, and a fifth sealing layer (aluminumoxide layer) were formed on the PET film substrate in that order.

Comparative Example 1

[0201] A 1% methyl methacrylate THF solution is spin coated on a PETfilm (with a thickness of 100 μm) with a size of 100 mm×100 mm, dried,and subjected to UV lamp exposure to form a polymer layer with athickness of 200 nm on the film. Subsequently, the resulting film wasfixed in a holder of a vacuum deposition apparatus available on themarket, and after that, pressure in the vacuum chamber of the apparatuswas reduced to 2×10⁻⁴ Pa. Then, a sealing layer (an aluminum oxidelayer) was vacuum deposited on the polymer layer to give a thickness of200 nm.

[0202] The process forming two layers described above was repeated twotimes. Thus, support D (comparative) was obtained.

[0203] The process forming two layers described above was repeated threetimes, employing another PET film. Thus, support E (comparative) wasobtained.

[0204] The process forming two layers described above was repeated fivetimes, employing another PET film. Thus, support E (comparative) wasobtained.

[0205] (Peeling Test)

[0206] Cross cut test as described in JIS K5400 was carried out. Elevenlines were cut at an interval of 1 mm in the transverse and longitudinaldirections on the layer surface with a single-edged blade normal to thelayer surface to form one hundred 1 mm square grids. Then, cellophaneadhesive tape available on the market was applied to the grid surface,and the tape, with one edge unattached, was sharply peeled away from thesurface at an angle of 90°. The rate of the area of the peeled layer tothe area of the adhered tape was calculated, and evaluation was carriedout according to the following criteria.

[0207] A: The rate of the area of the peeled layer to the area of theadhered tape was from 0% to less than 0.5%.

[0208] B: The rate of the area of the peeled layer to the area of theadhered tape was from 0.5% to less than 10%.

[0209] C: The rate of the area of the peeled layer to the area of theadhered tape was not less than 10%.

[0210] The results are shown in Table 1. TABLE 1 Support Peeling testRemarks A A Inventive B A Inventive C A Inventive D B Comparative E BComparative F B Comparative

[0211] The inventive samples prepared according to the atmosphericpressure plasma method exhibited good result in the peeling test,compared with the comparative samples. This is considered to be due tothe reason that the inventive samples had a more flexible layer ascompared to the comparative samples.

[0212] [Preparation of Organic EL Element Employing the Support of theInvention]

[0213]FIG. 11 is a sectional view showing the constitution of theorganic EL element prepared. A transparent conductive layer, an IZO(indium zinc oxide) layer was formed on the silicon oxide layer of thesupport A (of the invention) prepared above as a transparent supportaccording to a DC magnetron sputtering method, employing, as asputtering target, a sintering substance comprised of a mixture ofindium oxide and zinc oxide (In/(In+Zn)=0.80 by mole). Pressure in thevacuum chamber of the sputtering apparatus was reduced to 1×10⁻³ Pa,then a mixed gas of an argon gas and an oxygen gas(argon:oxygen=1000:2.8 by volume) was introduced until pressure in thevacuum chamber reached not more than 1×10⁻¹ Pa, and the transparent IZO(indium zinc oxide) conductive layer was formed at a target voltage of420 V at a support temperature of 60° C. according to the DC magnetronmethod to obtain a thickness of 250 nm. The resulting IZO layer wassubjected to patterning to form an anode, and subjected to ultrasonicwashing in isopropyl alcohol, dried with a nitrogen gas, and furthersubjected to UV-ozone cleaning for 5 minutes.

[0214] An a-NPD layer with a thickness of 25 nm, a CBP and Ir(ppy)₃co-disposition layer with a thickness of 35 nm (a disposition speedratio of CBP to Ir(ppy)₃ being 100:6), a BC layer with a thickness of 10nm, and an Alq₃ layer with a thickness of 40 nm were formed as anorganic EL layer in that order on the transparent conductive layer andfurther, a lithium fluoride layer with a thickness of 0.5 nm was formedon the Alq₃ layer as cathode buffering layer (not illustrated in detailin FIG. 11). Further, a 100 nm thick cathode of aluminum was formed onthe lithium fluoride layer through a mask pattern.

[0215] The support A (as the support 5 of FIG. 11) was superposed on thecathode of the thus obtained laminate under a nitrogen atmosphere. Thusan organic EL element sample OLED-1 was prepared. FIG. 11 shows thestructure in that the transparent electrode and the aluminum cathodewere sealed employing a photo-curable epoxy resin adhesive and a part ofthe transparent electrode and a part of the aluminum cathode can be usedas electrical terminals.

[0216] Organic EL element samples OLED-2, 3, 4, 5, and 6 were preparedin the same manner as in organic EL element sample OLED-1 of Example 1,except that supports B, C, D, E and F were used, respectively, insteadof support A.

[0217] The light emission layer of each of the above-obtained organic ELelement samples was evaluated as follows.

[0218] Nine volts were applied to each sample, and the light emittedportion was photographed at a factor of 50 power to obtain a firstphotographic image of the light emitted portion. Further, each samplewas subjected to folding test in which the sample was folded by an angleof 45°, and returned to the original position, which was repeated 1000times, and then the sample was aged for 100 hours at 50° C. and 80% RH.Then, nine volts were applied to the resulting sample, and the lightemitted portion was photographed at a factor of 50 power to obtain asecond photographic image of the light emitted portion. The areas ofdark spots in the first and second photographic images were measured,and the dark spot area increase rate defined by the following formulawas calculated.

Dark spot area increase rate (%)=(Dark spot area in the secondphotographic image−Dark spot area in the first photographicimage)×100/Dark spot area in the first photographic image

[0219] The dark spot area increase rate obtained above was evaluatedaccording to the following criteria:

[0220] E: The dark spot area increase rate was not less than 20%.

[0221] D: The dark spot area increase rate was from 15% to less than20%.

[0222] C: The dark spot area increase rate was from 10% to less than15%.

[0223] B: The dark spot area increase rate was from 5% to less than 10%.

[0224] A: The dark spot area increase rate was less than 5%.

[0225] The results are shown in Table 2. TABLE 2 Organic EL Support Darkspot area element sample used increase rate Remarks OLED-1 A C InventiveOLED-2 B B Inventive OLED-3 C A Inventive OLED-4 D E Comparative OLED-5E D Comparative OLED-6 F D Comparative

[0226] As is apparent from Table 2, organic EL element samples OLED-4, 5and 6 (comparative samples), employing comparative supports D, E and F,respectively, exhibited poor results in the folding test. This isconsidered to be due to the reason that cracks, produced in the layer bythe folding test, could not prevent moisture in air from penetratinginto the layer of the samples. Inventive organic EL element samplesemploying inventive supports A, B or C exhibited minimized deteriorationdue to folding test, and provided excellent resistance to folding, whichwere proved to be suitable for flexible displays.

Example 4

[0227] A silicon oxide layer was formed on a 100 μm thick polyethyleneterephthalate film, and supports described later were prepared accordingto the procedures as described below. Formation of the silicon oxidelayer according to an atmospheric pressure plasma CVD method was carriedout employing the plasma layer formation apparatus as shown in FIG. 1.

[0228] Formation of a silicon oxide layer having a carbon concentrationof 3 atomic % was carried out employing the gas composition used andpower supplied as shown below (hereinafter referred to as Condition A).Composition of gas used Inert gas: argon 98.25% by volume Reactive gas1: hydrogen 1.5% by volume Reactive gas 2: tetraethoxysilane vapor 0.25%by volume (gasified by being bubbled with argon)

[0229] Power Supplied:

[0230] A power of 1 W/cm² with a frequency of 13.56 MHz was supplied.

[0231] Formation of a silicon oxide layer having a carbon concentrationof 0.01 atomic % was carried out employing the gas composition used andpower supplied as shown below (hereinafter referred to as Condition B).

[0232] Composition of Gas Used

[0233] The same gas composition as in Condition A above was used.

[0234] Power Supplied:

[0235] A power of 10 W/cm² with a frequency of 13.56 MHz was supplied.

[0236] The carbon concentration in the silicon oxide layer of each ofthe supports described below was determined employing a dynamicsecondary ion-mass spectrography (hereinafter referred to also asdynamic SIMS). Regarding the dynamic secondary ion-mass spectrography(dynamic SIMS), JITSUYO HYOMEN BUNSEKI NIJIION SITSURYO BUNSEKI editedby HYOMEN KAGAKUKAI (2001, MARUZEN) is referred to. In the invention,dynamic SIMS measurement was carried out under conditions as shownbelow.

[0237] Spectrometer used: ADEPT 1010 produced by Physical ElectronicsCo., Ltd. or TYPE 6300 secondary ion mass spectrometer Primary ion used:Cs Primary ion energy: 5.0 KeV Primary ion current: 200 nA Area radiatedby primary ion: 600 μm square Absorption rate of secondary ion: 25%Secondary ion polarity: Negative Secondary ion to be detected: C⁻

[0238] The carbon concentration in the silicon oxide layer is determinedunder the conditions as described above. Firstly, based on the carbonconcentration of a standard silicon oxide layer, which is determinedaccording to a Rutherford back scattering spectrography, and intensityof the carbon ion of the standard silicon oxide layer obtained accordingto the dynamic SIMS, relative sensitivity coefficient is obtained. Next,based on the intensity of the carbon ion of a silicon oxide layer of asample to be measured obtained according to the dynamic SIMS and therelative sensitivity coefficient obtained above, the carbonconcentration of the sample is computed. In the invention, the carbonconcentration of the silicon oxide layer is measured through the entirethickness thereof to obtain a depth profile of the carbon concentration.Carbon concentrations are obtained at portions from 15 to 85% of thethickness from the depth profile obtained above, and the average thereofis defined as the carbon concentration in the invention. Thus, thecarbon concentration of the silicon dioxide layer is obtained in termsof atomic % as represented by the following formula:

Carbon concentration (atomic %) in the silicon oxide layer=(Number ofcarbon atoms)×100/(Number of all atoms)

[0239] (Preparation of Support G)

[0240] A silicon oxide layer was formed on a 100 μm thick polyethyleneterephthalate film according to an RF sputtering method (frequency:13.56 MHz) employing silicon oxide as a sputtering target to obtain athickness of 880 nm. Thus, comparative support G was obtained.

[0241] The carbon concentration of the formed silicon oxide layer wasless than the lowest limit capable of being detected according to themethod described above.

[0242] (Preparation of Support H)

[0243] A silicon oxide layer was formed on a 100 μm thick polyethyleneterephthalate film according to an atmospheric pressure plasma CVDmethod employing the condition A described above to obtain a thicknessof 880 nm. Thus, support H was obtained.

[0244] (Preparation of Support I)

[0245] A silicon oxide layer was formed on a 100 μm thick polyethyleneterephthalate film according to an atmospheric pressure plasma CVDmethod employing the condition B described above to obtain a thicknessof 880 nm. Thus, support I was obtained.

[0246] (Preparation of Support J)

[0247] A first silicon oxide layer was formed on a 100 μm thickpolyethylene terephthalate film employing the condition A describedabove to obtain a thickness of 220 nm, a second silicon oxide layer wasformed on the first layer employing the condition B described above toobtain a thickness of 220 nm, a third silicon oxide layer was formed onthe second layer employing the condition A described above to obtain athickness of 220 nm, and a fourth silicon oxide layer was formed on thethird layer employing the condition B described above to obtain athickness of 220 nm. Thus, support J having four silicon oxide layerswas obtained.

[0248] (Preparation of Support K)

[0249] A fifth silicon oxide layer was formed on the fourth siliconoxide layer of the support J obtained above, employing the condition A,to obtain a thickness of 220 nm, and a sixth silicon oxide layer wasformed on the fifth silicon oxide layer employing the condition B toobtain a thickness of 220 nm. Thus, support K having six silicon oxidelayers was obtained.

[0250] Organic EL element samples OLED-7, 8, 9, 10, and 11 were preparedin the same manner as in organic EL element sample OLED-1 of Example 1,except that supports G, H, I, J and K were used, respectively, insteadof support A.

[0251] When DC 9 volts are applied to these organic EL element samples,green light was emitted. The luminance half-life of light emitted fromthe organic EL element samples OLED-8, 9, 10, and 11 was expressed by arelative value (hereinafter referred to also as relative luminancehalf-life) when the luminance half-life of light emitted from the sampleOLED-7 was set at 100. The results are as follows:

[0252] OLED-8 (123), OLED-9 (142), OLED-10 (425), OLED-11 (641)

[0253] The value in the parenthesis represents the relative luminancehalf-life.

[0254] As is apparent from the above, organic EL element samplesemploying the supports of the invention provided long lifetime.

[0255] [Effects of the Invention]

[0256] The present invention can provide a support with high moisturesealing property and without layer exfoliation, which is useful as adisplay or an electronic device, and an organic electroluminescenceelement with long life employing the supports.

What is claimed is:
 1. A support comprising a flexible substrate andprovided thereon, one or two or more polymer layers and one or two ormore sealing layers, wherein at least one of the polymer layers and thesealing layers is formed by a process comprising the steps of exciting areactive gas at a space between opposed electrodes at atmosphericpressure or approximately atmospheric pressure by electric discharge tobe in the plasma state, and exposing the flexible substrate, the polymerlayer, or the sealing layer to the reactive gas in the plasma state. 2.The support of claim 1, wherein the polymer layer contains a polymericcompound, and the sealing layer contains a metal oxide, a metal nitrideor a metal oxide nitride.
 3. The support of claim 2, wherein thepolymeric compound is obtained by polymerization of a monomer comprisinga vinyl compound or an acetylene compound, the metal oxide is a compoundselected from silicon oxide, titanium oxide, indium oxide, tin oxide,indium tin oxide (ITO), or alumina, the metal nitride is a compoundselected from silicon nitride or titanium nitride, the metal oxidenitride is a compound selected from silicon oxide nitride, or titaniumoxide nitride, and the reactive gas is an organometallic compound or themonomer.
 4. The support of claim 3, wherein the organometallic compoundis an organosilicon compound, an organotitanium compound, an organotincompound, an organoindium compound, an organoaluminum compound, or acomposite compound thereof.
 5. The support of claim 4, wherein theorganosilicon compound is a compound represented by formula (1), (2),(3), or (4), Formula (1)

wherein R₂₁, R₂₂, R₂₃, R₂₄, R₂₅ and R₂₆ independently represent ahydrogen atom or a monovalent substituent, and n1 represents a naturalnumber. Formula (2)

wherein R₃₁ and R₃₂ independently represent a hydrogen atom or amonovalent substituent, and n2 represents a natural number.(R₄₁)_(n)Si(R₄₂)(_(4−n))   Formula (3) wherein R₄₁ and R₄₂ independentlyrepresent a hydrogen atom or a monovalent substituent, and n representsan integer of from 0 to
 3. Formula (4)

wherein A represents a single bond or a divalent group, R₅₁, R₅₂, R₅₃,R₅₄, and R₅₅ independently represent a hydrogen atom, a halogen atom, analkyl group, a cycloalkyl group, an alkenyl group, an aryl group, anaromatic heterocyclic group, an amino group or a cyano group, providedthat R₅₁ and R₅₂, or R₅₄ and R₅₅ may combine with each other to form aring.
 6. The support of claim 5, wherein the compound represented byformula (4) is a compound represented by formula (5), Formula (5)

wherein R₆₁, R₆₂, R₆₃, R₆₄, R₆₅, and R₆₆ independently represent ahydrogen atom, a halogen atom, an alkyl group, a cycloalkyl group, analkenyl group, an aryl group, or an aromatic heterocyclic group.
 7. Thesupport of claim 3, wherein the content of the metal oxide, the metalnitride and/or the metal oxide nitride in the sealing layer is not lessthan 90% by weight.
 8. The support of claim 1, wherein the sealing layercontains carbon in an amount of from 0.2 to 5% by weight.
 9. The supportof claim 1, wherein the sealing layer has a thickness of from 50 to 2000nm, and the polymer layer has a thickness of from 50 to 2000 nm.
 10. Thesupport of claim 1, wherein at least one of the sealing layers is formedby a process comprising the steps of exciting a reactive gas at a spacebetween opposed electrodes at atmospheric pressure or approximatelyatmospheric pressure by discharge to be in the plasma state, andexposing the flexible substrate to the reactive gas in the plasma state.11. The support of claim 1, wherein the sealing layer is formed by aprocess comprising the steps of exciting a reactive gas at a spacebetween opposed electrodes at atmospheric pressure or approximatelyatmospheric pressure by discharge to be in the plasma state, thedischarge being induced by supply of a power of not less than 1 W/cm²with a frequency exceeding 100 kHz, and exposing the flexible substrateto the reactive gas in the plasma state.
 12. An organicelectroluminescence element comprising a support, wherein the supportcomprises a flexible substrate and provided thereon, one or two or morepolymer layers and one or two or more sealing layers, wherein at leastone of the polymer layers and the sealing layers is formed by a processcomprising the steps of exciting a reactive gas at a space betweenopposed electrodes at atmospheric pressure or approximately atmosphericpressure by discharge to be in the plasma state, and exposing theflexible substrate to the reactive gas in the plasma state.
 13. Asupport comprising a substrate and provided thereon, at least two layerscontaining a metal oxide, a metal nitride or a metal nitride oxide, thetwo layers being different in carbon concentration, wherein at least oneof the layers is formed by a process comprising the steps of exciting areactive gas at a space between opposed electrodes at atmosphericpressure or approximately atmospheric pressure by electric discharge tobe in the plasma state, and exposing the substrate or the layer on thesubstrate to the reactive gas in the plasma state.